Watch crystal



Patented pr. 29, 1952 UNITED STATES PATENT OFFICE Claims.

The present invention relates to watches and indicating instruments and more particularly to improved crystals and means for applying, retaining and removing such crystals from these instruments.

, Considerable difliculty is frequently met with in reading the position of the hands of watches or clocks, or the pointing needles of other and similar instruments due to reflections and glare from the glass crystal surface. Under certain conditions, particularly when the light source is intense or concentrated, such as outdoors in bright sunlight, it is frequently necessary to move either the instrument or the readers head, or both, before the dial and hands can be seen clearly through the crystal. In the case of pocket or wrist watches this diflculty can usually be overcome by tilting the watch until the reflected light no longer strikes the eyes, but this is not always convenient to do, particularly when the watch or instrument is fixed upon a wall or instrument panel.

This invention is more particularly directed toward reducing and eliminating the reflected light and glare from watch and instrument crystals. The applicant has found' that a concave or conic crystal permits greater visibility and appreciably less glare than existing crystals under the same lighting conditions. The invention also resides in a novel crystal retention means as well as in an improved tool for flexing the crystal and facilitating its application and removal from its bezel or frame.

4It is accordingly a major object of this invention to provide an improved unbreakable crystal for watches and other devices from which the glare and reflected light is materially reduced. It is a corollary object to provide a crystal which permits of improved visibility of the hands or indicating means without the necessity of tilting the watch or other device or changing the viewpoint of the observer. An additional object lies in an improved form of concave or conic crystal having a exing retention edge which is readily and positively attached to 'a bezel. Av further object resides in providing a simple vacuum producing tool for deforming or flexing the crystal such that it may readily be inserted within and removed from its retaining bezel.

Other objects and advantages of the present invention will become apparent to those skilled in the art after reading the present description together with the accompanying drawings forming a part hereof, in which:l

Fig. 1 is a sectional elevation of a preferred form of my improved crystal as applied to a timepiece, showing the application tool in an operative position thereon; and

Fig. 2 is a similar cross-sectional elevation of another form of my improved crystal also applied to a time-piece.

Referring now to Fig. l the framework of a watch is indicated at 5 and has attached thereto a face or dial 6 on which numerals or other suitable indicia may be carried or indicated. It will be understood that this invention is equally applicable to any other indicating device or meter and in the case of watches or clocks there may also be provided supplementary means for indicating seconds, days, months or other information. The face 8 is suitably apertured to accommodate the usual shafts 'l to which are attached the hour and minute hands 8 and 9, respectively.

The case of the watch 5 is provided with a bezel or ring I0, having a rounded contact portion 10b, the bezel being attached to the watch framework by screw threads, a snap detent or other known means. The bezel Ill is provided with an inwardly opening V-groove er recess lila which extends circumferentially around its l open central portion in the region of the periphery of the dial face 6.

The crystal ll is preferably formed from a single homogeneous piece of transparent flexible or semi-flexible material such as Lucite or Plexiglas (methyl methacrylate) or other unbreakable plastic composition, or glass. It cornprises an outer conic concave viewing portion lla. and a circumferential beaded retaining portion 1lb-llc. The concave conic or depressed central portion Ila is preferably formed such that its transparent viewing portion slopes inwardly and downwardly at which the angle A is from 7 to 10 degrees and is preferably flattened or rounded at what would otherwise be the recessed central apex at Ile. Thecircumferential'bead llb-llcis formed into a compound curve or S-shape with the initial bead Hb outwardly rounded and the second bead llc inwardly rounded. The latter bead preferably terminates in an outwardly facing V-point Hd of a shape and diameter such that it engages the V-groove recess I lla in the bezel.

The applicator tool l2 comprises a tubular housing I3 having a lower flared or bell-mouthed portion 13a. Cylindrical guide blocks I4 and l5 are positioned within the'tube i3, being axially retained therein by. the rivets 13b passing through the wall of the tube. The lower guide I4 is bored at Ida to slidingly receive the stem or rod I6 and the upper guide I5 is provided with an internally threaded portion at I5a to engage the threaded portion 16a of the stem. The latter is provided at its upper end with a thumb wheel I1, and at its lower end with a flange I6b adapted to be embedded within a rubber vacuum cup I8 having a beveled rim portion I8a. This rubber cup is formed such that its periphery makes sealing contact with the faceof thecrystal II, is backed by the flared portion I3a of' the tube, and defines a variable capacity vacuum or suction space I9 over the greater portion of the crystal surface. It will be understood that the latter may be of any suitable shape such as circular, oval, square or rectangular, although, in the latter shapes the corners are preferably rounded.

When it is desired to remove the crystal Il from the bezel I0 in Fig. l the thumb wheel Il' of the applicator I2 is first turned until the central portion of the rubber cup I8 is extended downwardlyV below its rim portion I8a. The latter is then preferably moistened and placed in sealing contact with the surface of the crystal in the position shown in Fig. 1. The thumb wheel is then rotated in the opposite direction through substantially the position shown in Fig. l wherein a vacuum space I9 is created between the cup I8 and the recessed portion of the crystal II. Continued deformation of the cup and increased vacuuin causes the apex portion. Ile to rise, or the upper or intermediate portion Ia of the crystal to lift and flatten itself. As this occurs the upper bead IIb is caused to flex or deform, with its upper part moving outwardly and its lower part moving inwardly and upwardly as a. result of its rolling contact with the rounded nose IIlb` of the bezel. This causes the lower bead IIC to be moved inwardly and upwardly and the V-edge IIb to be released from the V-gl'oove recess Ia in the bezel. In this flexed or deformed condition of the crystal II it may readily be removed from the bezel Il by upward movement of the tool I2 toA which it adheres by the aforesaid suction effect.` By a reversal of this procedure it` will be understood that the crystal may be inserted into the bezel and released from the tool by rotation of` the thumb wheel and the resulting reduction inv the suction or vacuum effect. It will be understood that the homogeneous crystal may be made with a transparent viewing portion and an opaque or colored peripheral portion. In certain installations the deformation of the lower bead is improved by cutting a number of slots I Is through the wall vertically and radially, but in all cases the slots are preferably kept below the sealing contact along Ib. Due to the flexibility of the plastic crystal of substantially uniform thickness particularly the lower half orthe slotted S.por tion IIe, the upward pull exerted by the applicator I2 will clause the V-edge IId to be pinched or constricted by the wedging effect of the upper slope of the V-recess Illa, and the crystal may then be lifted from within the bezel I0. The crystal may also be readily applied without the use of the applicator by manual pressure alone. which constricts the diameter across the V-edge I Id until it snaps into the V-recess Illa. due .tothe resilience of the portion IIc.

A modification of the improved glare-proof crystal, which does not require the use-of aV tool such as I2, is shown in Fig. 2. The watch framework has attached thereto.. an indicia-bearing dial 2.6 apertured for the shaft assembly 2'Iv carry- 4 ing the hands 28 and 29. A bezel, 30 preferably of metal, has an inner cylindrical or oval-shaped portion terminating in the end face 30h, and has an inwardly beveled part 30a which is adapted to engage the complementary beveled periphery ,25a of the watch plate 25. The crystal 3| has a similar transparent viewing portion 3Id which is conic and concave terminating in a rounded center portion 3Id. The crystal 30 is formed with a cylindrical wall portion 3Iby which ts within the like cylindrical or oval-shaped wall portion of the bezel. The crystal 30 is also formed with an outwardly turned ange 3Ic which is engaged by the inner end 30h of the bezel and by which it is retained against the dial 2G. As in the case of the crystal II shown in Fig. 1, the angle A is preferably from 7 to 10 degrees.

In order to apply the crystal 3I to the watch 25 it is first nested centrally within the bezel 3D such thatVI their cylindricalv or oval-shaped wall portions are telescoped within each other. The bezel 3G is then pressed down against the framework of the watch 25 co-axially with the face 26 until the beveled retaining edge 30a ofthe bezel is snapped over the outer edge 25a. The bezel and crystal combination is readily removed by the insertion of a knife blade or other sharp edge by means of which the retaining ring at the periphery or the bezel is pried or removed from the main case of the watch 25.

It will be obvious to those 'skilled in the art that the present invention is readily adapted to watches, clocks and a wide variety of indicating instruments and all such modifications both with respect to the general arrangement and the detailed form of the respective elements are intended to come within the scope and embrace of the invention as more particularly set forth in the appended claims.

I claim:

l. In a crystal for a watch having a bezel, a compound curved periphery on said crystal engageable with said bezel, s aid periphery having ay plurality of` radial slots and said crystal having a normally depressed portion adapted when nattenedto cause disengagement of said periphery from said bezel.

2. In al crystal for a watch, or like instrument, having a retaining bezel having a groove said crystal formed from a flexible transparent ma,- terial, a flexible periphery of S-shaped crosssection formed on said crystal engageable with said retainingy bezel groove, said periphery having a plurality of radialslots, and releasable from the bezel groove upon deformation of thecentral portion and periphery of said crystal.

3. In a watch or like instrument, a` retaining bezel having a V-groove, a homogeneous semi.

flexible crystal having a retaining peripheryl of Scrosssection, said periphery havingv a plurality of radial slots and a depressed central portion arranged in such manner that deformation of said periphery causes disengagement of said periphery from said bezel groove.

4. In a crystal for a. watch or like instrument, said instrument having an inwardly facing` V- shaped recess, a semi-flexible periphery on said crystal formed into an S-shaped cross-section a radially slotted free edge of which is arranged to engage said instrument recess by outward deformation of said S-shaped periphery.

5. In a watch or like instrument, a bezel having an inwardly facing groove,Y a crystal havinga periphery of S-shaped cross-section, the inner free edge of said crystal periphery engageable with said bezel groove, said inner free edge having a plurality of radially extending slots and flexibly 'dsengageable from said detent upon deformation of the intermediate portion of said 5 crystal.

KURTISS P. SCHENKE.

REFERENCES CITED UNITED STATES PATENTS Name Date Peterson May 12, 1914 15 Number Number Number 6 Name Date Loomis June 29, 1920 Pief June 30, 1931 Lindhe July 3, 1934 Putman Nov. 10, 1936 FOREIGN PATENTS Country Date Great Britain Jan. 26, 1914 Great Britain Apr. 19, 1893 Austria July 25, 1912 Great Britain Nov. 30, 1916 

